Remove eventTargetInheritance from WrapperTypeInfo

third_party/WebKit/Source/bindings/core/v8/V8Binding.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 777 matching lines @@
     return window->frame();
   // We return 0 here because |context| is detached from the Frame. If we
   // did return |frame| we could get in trouble because the frame could be
   // navigated to another security origin.
   return nullptr;
 }
 
 EventTarget* toEventTarget(v8::Isolate* isolate, v8::Local<v8::Value> value) {
   // We need to handle a DOMWindow specially, because a DOMWindow wrapper
   // exists on a prototype chain of v8Value.
   if (DOMWindow* window = toDOMWindow(isolate, value))

[Yuki, 2017/02/13 05:48:00]

I think we no longer need this hack.

https://crrev.com/2500363002 should have made the situation simpler, and now
(IIUC) you can simply apply HasInstance() API to the global proxy object, too. 
i.e. you can simply use V8EventTarget::toImpl(WithTypeCheck) for window, too.

     return window;
-  if (V8EventTarget::hasInstance(value, isolate)) {
-    v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(value);
-    const WrapperTypeInfo* wrapperTypeInfo = toWrapperTypeInfo(object);
-    if (wrapperTypeInfo->eventTargetInheritance ==
-        WrapperTypeInfo::NotInheritFromEventTarget)
-      return nullptr;
-    return static_cast<EventTarget*>(toScriptWrappable(object));
-  }
-  return nullptr;
+  return V8EventTarget::toImplWithTypeCheck(isolate, value);
 }
 
 void toFlexibleArrayBufferView(v8::Isolate* isolate,
                                v8::Local<v8::Value> value,
                                FlexibleArrayBufferView& result,
                                void* storage) {
   ASSERT(value->IsArrayBufferView());
   v8::Local<v8::ArrayBufferView> buffer = value.As<v8::ArrayBufferView>();
   if (!storage) {
     result.setFull(V8ArrayBufferView::toImpl(buffer));
@@ skipping 198 matching lines @@
   if (!v8Call(v8::JSON::Parse(isolate, v8String(isolate, stringifiedJSON)),
               parsed, tryCatch)) {
     if (tryCatch.HasCaught())
       exceptionState.rethrowV8Exception(tryCatch.Exception());
   }
 
   return parsed;
 }
 
 }  // namespace blink